I know I'm not leaving you guys alone about this article I am making, but before I write anymore, I need to know what you guys think (yeah its not done.) Am I adding to many symptoms? Is it paranormal enough for the site? Should I add a definition list? I want to know if the idea is good so I don't get way to into it only to be disappointed.

As far as I can tell this should be Euclid. Keter is for things that can't be easily contained or kept secret from public knowledge. Given that this thing can be kept contained if they feed it and change its water every now-and-then, it's Euclid.

Classification is not about the danger an object represents.

SCP-2380 is currently contained within a 22,712.5 liter pond located in Area-12 ( Biological Research Area-12 )

Overly-precise measurements with no given justification are normally frowned upon. Would it be a problem to keep it in a 22,714.7 liter pond instead? If not then this line is misleading. If the pond has to be bigger than a certain measurement to make managing the excretions easier you could justify a precise measurement, but you would need to say that the minimum is [insert measurement here] because it makes the excretions easier to deal with.

Why is it in a pond, which I can only assume is outside? Why isn't it in a reinforced glass aquarium containment inside, or a specially designed enclosure?

If the Foundation has to monitor the water levels, why not fill it to 23 kiloliters and make it easier to track?

with, surrounding the perimeter, 3 m iron walls.

"with 3m tall iron walls surrounding the perimeter."

Why iron walls as opposed to anything else?

Hebdomally

I think you mean Hebdomadally.

Also it's fine (better even) to just say weekly. It sticks in the tone SCPs are known for.

Hebdomally, 7570.8 liters of the containment tank's water is to be changed (1/3 of total amount).

"7570.8 liters of the containment tank's water is to be changed weekly (1/3 of total amount)."

If that's to keep it from filling with SCP-2380-A, wouldn't it be better to put SCP-2380 in a temporary containment and refill the entire thing? The creature is apparently amphibious, so it should be fine to leave it in a dry room for an hour and then clean the room when it's returned to the containment.

Should the removed water be disposed of in a specific way? If it's full of anomalous excretion then it probably should be.

That is a lot of stuff. How many of those could you cut out without killing the creature?

SCP-2380 must, at all times, be under be video surveillance.

Surveillance is usually implied.

If something has to be under specialist surveillance, the nature of the surveillance should be noted. IE "no cameras are to come within 15 meters of SCP-XXX," "SCP-XXX suveillance footage must be monitored by at least one member of security personnel at all times," etc.

Even so there has to be a reason. Since you want to use the gif, I would suggest saying that the levels of SCP-2380-A excretion change abruptly so it needs to be watched at all times for behavioral changes. If the speed suddenly rose by 2000% for example, the containment would be filled within a few hours and if someone wasn't monitoring it that would be a problem.

SCP-2380 ( commonly referred to as "Blinky" )

Nicknames in-universe should be avoided. Aé can get away with it because she can't speak proper English so using her actual name makes communicating easier. Cassy gets away with it because the name has been used to personify her further by the author so you care about her more, and in-universe is justified because Cassy is depressed about the nature of her existence. You'll notice that the ones with names like that are typically found in Series I or early Series II. Nowadays it's tacky.

"Blinky" would work well for a mainlist title though, since those are non-canon.

Measuring 1 m long with a girth of 61 cm, and approximately 13.7 kilograms.

I think you missed the word "weighing" somewhere in there.

SCP-2380 is, in appearance, a dead deteriorating fish copse. It has been found however to be alive

Copse should be corpse, I think?

You just said it's a fish, so we already know that part.

Define dead in appearance? I'm not sure that's a thing.

The photo doesn't look like a dead fish.

The only part here that works is "deteriorating." You could say "SCP-2380 exhibits rapid deterioration of tissue, though the creature appears unimpeded."

SCP-2380 has both rudimentary gills for breathing underwater, and uses it's air-breathing and land-walking capabilities to aestivate in the dry mud when it's pond dries up or travel to a new water source.

Does it have legs? I don't think you mentioned how it can move on land. I think I linked you to this already, but I think SCP-939 is a good standard when looking to describe a creature.

You never made mention of the third eye. Or the coloration of the creature. If it weren't for the photo I would be lost as to what it looks like.

"that greatly effects many things in it's environment" sounds like one of the parts that isn't done.

You never actually define it as SCP-2380-A. You just sort of start saying SCP-2380-A without telling the reader that it's this. After the above sentence, you should say "designated SCP-2380-A."

In humans, it creates dilutional hyponatremia like effects

"In humans" doesn't really mean anything. Do you mean on contact with human flesh? Do you mean upon ingestion?

I had to look up dilutional hyponatremia. I wasn't sure what it was. You should put a footnote1 explaining it in understandable terms. You make a footnote by typing what you want in the footnote [[footnote]]like so[[/footnote]].

What's SCP-2380-1? The sodium levels? The effect? I don't think you need to designate anything SCP-2380-1.

dropping it to a deadly >125 mEq/L.

Average readers aren't going to know what that means. I can assume from context it's bad, but for all I know it's technobabble.

The entire list of symptoms is just a trek through medical ramifications. And none are particularly interesting. Or anomalous.

The image tags down the bottom, I've never seen those. They're cool and all (I would have used these or these for that purpose since they're already SCP based and moderately well established by Containment Breach) but they come of as just a weird nonstandard inclusion. And even on one of those things I just linked to it says the classifications are no longer used. I would suggest nixing them.
The tags you've chosen as well, you aren't supposed to tag your articles yourself. The wiki has a team of people who do it for you, and you're supposed to leave them to it.

Overview: The science is pretty legit, and aside from a few issues the tone is alright, but it needs a lot of cleanup. More importantly, I'm not sure that it's especially anomalous in its current state. A highly venomous fish could exist. 3-eyed fish do exist (granted usually because of genetic disorders). It doesn't really do anything.
Reading the part about it deteriorating though gave me a thought, if you'd indulge me.

A suggestion to make it more anomalous: What if it is actually deteriorating and growing its tissue back at a stable rate? That breaks the laws of thermodynamics and conservation of mass, so there's 1 thing. Then, what if the tissue that falls off is SCP-2380-A? That ties in its appearance to the main anomaly and makes the excretion generally more dangerous already because it's conceivably infinite. That's 2. Then, one thing I thought of that might go against what you wanted to do but I'll suggest anyway, what if touching it causes increased decomposition of living tissues, causing it to become SCP-2380-A? Like if you touched it, you arm would start to decompose and you yourself would become SCP-2380-A within a few minutes and die from it?Or being exposed to it causes you to exhibit the same properties as SCP-2380, only stopping when you actually die. SCP-2380 would essentially assimilate other living creatures into the spread of the substance.

But things to bear in mind, whatever anomaly you come up with for the substance, death is not scary. Death is a release. If the death is interesting, that's good. If it's just death because death, that makes for a bland SCP.
If it's an assimilation, it needs to be different from assimilation hazards done before. If it's toxic, it has to be different from biohazards done before. What is there about your SCP that makes readers want to read it as opposed to other articles that do the same thing better?

Apologies if any of this seems harsh, and feel free to disregard any of my opinions.

What if it is actually deteriorating and growing its tissue back at a stable rate?

Are you saying that, while the skin is undergoing cellular reproduction, it is also falling away? That, I agree would be pretty cool. But what if it also continued to duplicate even after it has been shed? Yay or nay?

Wow, I like it. You were a huge help in this and I thank you, I still need to add the part about cellular reproduction and then I will be done, thank goodness. Please, read and give any final judgments.

Edit: hrm, just re-read the A suggestion to make it more anomalous: box. Yeah, the idea of your arm actually starting to decompose too would be pretty interesting. I will add a second tab and make the artical go around that, and afterwards see which one I favor most.

That is a whole lot of commas and a whole lot of information jumbled together. Some rewording is in order.

What is the actual purpose of the walls? How I'm thinking of it is if there's an integrity issue with the tank and samples of the substance get out, the walls are an extra precaution to keep the breach localized to that room. If that's the case, or not the case, justify why the walls are necessary.

SCP-2380's containment aquarium is to weekly, be emptied and powerwashed, eliminating all possible sources of SCP-2380-B.

As above, messy wording. The word weekly should be after the word powerwashed.

SCP-2380 is a mutant amphibious dark brown fish belonging to a species currently unidentified.

If they don't know the species, how do they know it's mutated?

SCP-2380 is, in appearance, deceased

I still don't think that means anything. Maybe say it's similar in appearance to a deceased/partially decomposed/whatever fish.

SCP-2380-B will cause nitrate levels to ascend up to ██ ppm

There's not much reason to keep that a secret.

If you have an actual number, just say it. It makes the article seem much more legit.

I'm not sure the inclusion of the worms does anything for the article. If would make more sense if SCP-2380-B was doing everything. Sometimes less is more.

SCP-2380 was originally found by fisherman Ronald Baker in the Chorro de Agua Caliente reservoir in Argentina, which receives water from a nuclear plant in the province of Córdoba.

And what did the Foundation do about it? I assume administer amnestics and check the area for more specimens?

As well as everything above, there are a lot of weird wording and grammatical choices. Read over your work out loud and see how it sounds to you.

Overview: A fair bit to go yet on presentation. On top of that, you really have to sell the anomalous effect. The main focus you've set is on that and not any story or emotional response, so it has to be enough to really grab the reader.
Keep at it, and always expect a handful of average drafts before getting the perfect one.

What is the actual purpose of the walls? How I'm thinking of it is if there's an integrity issue with the tank and samples of the substance get out, the walls are an extra precaution to keep the breach localized to that room.

It is to prevent any on land attemps of escape, being amphibious, i thought the reason of the walls would be obvious. I'll fix it.

Alright. I have checked, double checked, triple checked, and quadruple checked. I did everything from the +as promised, a line-by-line to the I'm going to do this here and not on the duplicate thread. I have made this as interesting as I can. Had my friend read it, thought it was so-so. I am done with SCP for today, so while I am gone, I need someone, ( Cupertino you can take a rest if you want ) to read over it and tell me, pros, and cons.

SIDE: I most likely will not post this exact draft, I will probably make multiple drafts before I post the real thing. prepare for true beauty.